SHA1.java

package com.circlegate.liban.utils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class SHA1 {

    /**
     * Encodes given string using SHA1 algorithm and UTF-8 charset.
     *
     * @param text
     * @return
     * @throws java.security.NoSuchAlgorithmException
     * @throws java.io.UnsupportedEncodingException
     */
    public static String encode(String text) throws NoSuchAlgorithmException,
            UnsupportedEncodingException {
        return encode(text, "utf-8");
    }

    /**
     * Encodes given string using SHA1 algorithm and given charset.
     *
     * @param text
     * @param charset
     * @return
     * @throws java.security.NoSuchAlgorithmException
     * @throws java.io.UnsupportedEncodingException
     */
    public static String encode(String text, String charset)
            throws NoSuchAlgorithmException,
            UnsupportedEncodingException {
        MessageDigest md;
        md = MessageDigest.getInstance("SHA-1");
        byte[] sha1hash = new byte[40];
        md.update(text.getBytes(charset), 0, text.length());
        sha1hash = md.digest();
        return convertToHex(sha1hash);
    }

    private static String convertToHex(byte[] data) {
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < data.length; i++) {
            int halfbyte = (data[i] >>> 4) & 0x0F;
            int two_halfs = 0;
            do {
                if ((0 <= halfbyte) && (halfbyte <= 9))
                    buf.append((char) ('0' + halfbyte));
                else
                    buf.append((char) ('a' + (halfbyte - 10)));
                halfbyte = data[i] & 0x0F;
            } while (two_halfs++ < 1);
        }
        return buf.toString();
    }

}